WALLACE STATE OFFICE BUILDING / 502 EAST 9th STREET / DES MOINES, IOWA 50319

515-281-5918 TDD 515-242-5967 FAX 515-281-6794 www.iowadnr.com

Converting Existing Underground Storage Tank (UST) Systems to

Ethanol Compatible

As higher percentages of ethanol (greater than 10% ethanol by volume) or E-blend are blended

with gasoline, owners and operators must ensure their UST systems are compatible. What may

have been compatible with E10 is probably not compatible with a higher percent ethanol blend.

Before you store or dispense E-blend, such as E85, you must verify that your ethanol fuel path

is compatible.

Ethanol guidance was developed through DNR meetings with the Fire Marshal Division, the

ethanol industry, petroleum marketers, installers and the insurance industry. The concerns

regarding E-blend are based on reviews of available literature and research documents, which

are listed at the end of this guidance document. The conclusion regarding E-blend fuel is

straightforward: without converting to compatible equipment, your UST system could degrade

and a product release could occur. Ultimately, the equipment and components must be

compatible with the product stored.

Concerns with E-blend Fuel

Compatibility. Iowa law [567-135.4(3)] and NFPA 30, 2000 Edition (2.2.2) require UST

systems to be compatible with the product stored. Components and equipment used for

storing/dispensing conventional fuels are time tested for compatibility and readily available

through your petroleum supplier. E-blend, however, does not have the same compatibility

characteristics of conventional fuels when it comes to storage and dispensing. Soft metals such

as zinc, brass or aluminum, which are commonly found in conventional fuel storage and

dispensing systems, are not compatible with E85. Steel tanks and piping must be UL Marked or

certified by the manufacturer for use with E-blend Fuels.

Some nonmetallic materials may also degrade when in contact with ethanol such as natural

rubber, polyurethane, adhesives (used in older fiberglass piping), certain elastomers and

polymers used in flex piping, bushings, gaskets, meters, filters, and materials made of cork. In

order to store and dispense E-blend fuel, fiberglass and steel UST systems/components must

be listed by UL Marked or certified by the manufacturer for use with E-blend fuels.

If you have concerns about specific storage and dispensing equipment, see New England

Interstate Water Pollution Control Commission (NEIWPCC), Health and Environmental Impacts

of Adding Ethanol to Gasoline in the Northeast States, July 2001, pp. 70-71. A list of E85

compatible equipment can be found at http://www.e85fuel.com/information/manufacturers.htm.

Phase Separation. Ethanol is completely miscible (mixable) in water. Ethanol also blends well

with gasoline. When water infiltrates a tank, (e.g., through sump covers and loose fittings at the

top of the tank), the ethanol in the ethanol-gasoline blend will absorb the water, which, if enough
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is present, will overwhelm the ethanol’s capacity to remain blended with the gasoline. Because

it mixes easier with water, the ethanol will be drawn from the gasoline into the water at the

bottom, separating from the gasoline. The product in the tank is no longer a blend of ethanol

and gasoline, but two layers of product--a layer of gasoline on top and an ethanol layer on the

bottom. You’re not getting an ethanol blend anymore, but a greater concentration of ethanol or

gasoline. Phase separation can be a problem for vehicles’ fuel lines as the product is no longer

an ethanol blend.

Accelerated Corrosion and Conductivity. Ethanol can accelerate corrosion in steel UST

systems by scouring or loosening deposits on the internal surfaces of tanks and piping. If a

corrosion cell exists, the ethanol can accelerate (scour) the corrosion cell and cause a

perforation. As mentioned above, ethanol is not compatible with soft metals such as zinc, brass,

copper, lead, and aluminum. These metals will degrade or corrode in contact with ethanol and

possibly contaminate a vehicle’s fuel system.

Tank leak detection equipment composed of certain metals (mentioned above), polymers and

elastomers may not be compatible with ethanol. Because ethanol has a higher conductivity

than gasoline, capacitance probes will not work in ethanol-blend fuels. Verify the floats used in

magnetostrictive probes are alcohol compatible and that the ATG system is properly calibrated

for ethanol.

Starting the Process of Converting to E-blend

The conversion to E-blend fuel requires time and effort to evaluate existing equipment, verify

compatibility and order ethanol compatible equipment. Costs are also an important

consideration. There is a new three-year $13 million renewable fuel infrastructure program that

provides grants to E-blend or biodiesel retailing sites. Grants can be applied for through the

Iowa Department of Economic Development by clicking here.

Here are some of the procedures you will have to follow in converting your system to E-blend.

The specific details are included in a separate checklist, which the owner and Iowa licensed

installer or professional engineer will have to complete and submit to the department.

1. Start the conversion process by obtaining the checklist of items that must be completed and

signed before your system can store and dispense a E-blend.

2. You will need to verify that components in the fuel path are compatible with the E-blend to be

stored and dispensed. Contact your petroleum equipment supplier or an Iowa licensed

installer to discuss converting to a higher percent ethanol blend and purchasing the

appropriate equipment. A list of licensed installers is available on our website (see p. 4).

The following equipment/components/materials must be compatible with the ethanol blend

you intend to store and dispense (see the checklist for more details):

• Auto shutoff or overfill valve

• Tank (Is the warranty in effect? Is it approved by manufacturer or UL listed for E-blend?)

• Submersible Pump, O-rings and gaskets

• Line leak detectors

• Leak Detection Equipment (ATG probes, floats, sump sensors)

• Piping material (UL listed or approved by manufacturer)
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• Thread sealant

• Flex connectors, grommets

• Filters

• Dispensers and hanging hardware (allow two-year phase in for compatibility)

• Spill containment and sumps

3. Your UST insurance carrier must be informed of your plans to convert to a higher percentage

ethanol. They may have other requirements other than what the department requires. The

checklist requires an amended certificate of insurance.

4. No level of water is acceptable for ethanol blend fuel due to the phase separation problems.

You will need to make certain all fittings and connections at the top of the tank are tight (no

vapors escape and no water enters) and that all sump and spill containment covers prevent

water from entering. Any water intrusion problems must be fixed

5. Contact the National Ethanol Vehicle Coalition (NEVC) at 877.485.8595. The NEVC provide

grants for the labors and materials for converting to ethanol from conventional fuels.

6. Determine costs and make your decision regarding the conversion. If you decide to convert,

make all necessary arrangements for the conversion with your petroleum supplier or

licensed installer.

7. The tank dedicated to E-blend must be clean. After any water problems have been fixed,

you must clean the tank dedicated to E-blend to remove all sludge from the bottom of the

tank. Any sludge or particulates in the bottom of the tank will be suspended in the ethanol

and cause problems with filters and fuel lines. Obtain a Clean Tank Certificate or similar

documentation from the tank cleaner after the tank is cleaned.

8. Fill pipe and access covers must be properly identified (API RP 1637 color code). We don’t

want the transport driver to mistakenly deliver E85 to an E10 tank.)

9. The owner and an Iowa licensed installer or professional engineer must sign the ethanol

compatibility checklist and submit it to the DNR. A copy of the revised certificate of

insurance and the Clean Tank Certificate must accompany the checklist.

First Delivery and Ongoing Maintenance

1. Follow normal delivery procedures for the first delivery of E-blend. The Renewable Fuels

Association (RFA) recommends filling the tank to 80 percent capacity and to keep the tank

as full as possible for 7 to 10 days1

2. As soon as product stabilizes, a precision test (0.1 gph leak rate) is conducted with your

ATG system to make sure your system is tight and the leak detection equipment is operating

properly. Report any Fail results.

 

1

 Renewable Fuels Association (RFA), Fuel Ethanol, Industry Guidelines, Specifications and Procedures,

December 2003, p. 15
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3. You must test for water (use alcohol compatible paste if you stick your tanks) at the

beginning of each shift for the first 48 hours after delivery.2 Checking for water regularly is a

part of the ongoing maintenance with ethanol storage.

Safe Handling

The safety equipment and precautions used for handling gasoline apply to ethanol and ethanol

blend (API 1626).

Spills and Releases

Ethanol blend spills and releases should be handled as they would be with gasoline. Notify the

proper authorities including DNR Emergency Response at 515.281.8694 or 515.281.8941.

Sources:

1. New England Interstate Water Pollution Control Commission (NEIWPCC), Health, Environmental and

Economic Impacts of Adding Ethanol to Gasoline in the Northeast States, Volumes 1 and 3, July

2001.

2. Renewable Fuels Association, Fuel Ethanol: Industry Guidelines, Specifications and Procedures,

RFA Publication #960501, Revised December 2003.

3. US Department of Energy, National Renewable Energy Laboratory: Handbook for Handling, Storing,

and Dispensing E85, April 2002

4. US Army Information Paper, Subject: Fuel Ethanol (E85).

5. State of Delaware, Department of Natural Resources and Environmental Control, Tank Management

Branch, Memorandum, Subject: Storing, Dispensing and Using Ethanol Fuel (E85), September 8,

2004.

6. Memorandum: Water Phase Separation in Oxygenated Gasoline (corrected version) by David

Korotney, EPA, Chemical Engineer, Fuels Studies and Standards Branch

7. American Petroleum Institute, Storing and Handling Ethanol and Gasoline-Ethanol Blends at

Distribution Terminals and Service Stations, API Recommended Practice 1626, First Edition, April

1985, Reaffirmed June 2000.

8. National Fire Protection Association (NFPA) 30, Flammable and Combustible Liquids Code, 2000

Edition; NFPA 30A Code for Motor Fuel Dispensing Facilities and Repair Garages, 2000 Edition

9. Compatibility and Permeability of Oxygenated Fuels to Materials in Underground Storage and

Dispensing Equipment, Paul A. Westbrook, Ph.D., Shell Oil Company, January 1999

10. Federal Transit Administration, Clean Air Program: Summary Assessment of the Safety, Health,

Environment and System Risks of Alternative Fuel, Final Report, 1995.

Websites

To download DNR’s checklist for converting your UST system to E-blend or to view a list of

licensed installers see

http://www.iowadnr.com/land/ust/index.html

For the Iowa Renewable Fuels Association (IRFA) see

http://www.Iowarfa.org/

For a listing of equipment approved to handle, store and dispense E85 see

http://www.pei.org/altfuels/guide.asp

For the Department of Energy, Energy Efficiency and Renewable Energy see

http://www.eere.energy.gov/afdc/infrastructure/fuel_inf.html

To view the Iowa Fire Marshall ethanol website:

http://www.dps.state.ia.us/fm/flammable/E-85.shtml

 

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 Ibid.
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v. Ethanol Conversion 11.21.06